53 lines
2.8 KiB
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53 lines
2.8 KiB
HTML
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<!Converted with LaTeX2HTML 0.6.5 (Tue Nov 15 1994) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds >
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<TITLE>2.2.5. String Characters</TITLE>
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<meta name="description" value=" String Characters">
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<meta name="resource-type" value="document">
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<P>
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<b>Common Lisp the Language, 2nd Edition</b>
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<BR> <HR><A NAME=tex2html1830 HREF="node27.html"><IMG ALIGN=BOTTOM ALT="next" SRC="icons/next_motif.gif"></A> <A NAME=tex2html1828 HREF="node21.html"><IMG ALIGN=BOTTOM ALT="up" SRC="icons/up_motif.gif"></A> <A NAME=tex2html1824 HREF="node25.html"><IMG ALIGN=BOTTOM ALT="previous" SRC="icons/previous_motif.gif"></A> <A NAME=tex2html1832 HREF="node1.html"><IMG ALIGN=BOTTOM ALT="contents" SRC="icons/contents_motif.gif"></A> <A NAME=tex2html1833 HREF="index.html"><IMG ALIGN=BOTTOM ALT="index" SRC="icons/index_motif.gif"></A> <BR>
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<B> Next:</B> <A NAME=tex2html1831 HREF="node27.html"> Symbols</A>
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<B>Up:</B> <A NAME=tex2html1829 HREF="node21.html"> Characters</A>
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<B> Previous:</B> <A NAME=tex2html1825 HREF="node25.html"> Character Attributes</A>
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<HR> <P>
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<img align=bottom alt="old_change_begin" src="gif/old_change_begin.gif"><br>
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<H2><A NAME=SECTION00625000000000000000>2.2.5. String Characters</A></H2>
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<P>
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Any character whose bits and font attributes are zero may be contained
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in strings. All such characters together constitute a subtype of
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the characters; this subtype is called <tt>string-char</tt>.
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<br><img align=bottom alt="old_change_end" src="gif/old_change_end.gif">
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<P>
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<img align=bottom alt="change_begin" src="gif/change_begin.gif"><br>
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X3J13 voted in March 1989 (CHARACTER-PROPOSAL) <A NAME=1023> </A>
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to eliminate the type <tt>string-char</tt>.
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Two new subtypes of <tt>character</tt> are <tt>base-character</tt>,
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defined to be equivalent to the result of the function call
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<P><pre>
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(upgraded-array-element-type 'standard-char)
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</pre><P>
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and <tt>extended-character</tt>, defined to be equivalent to the type specifier
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<P><pre>
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(and character (not base-character))
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</pre><P>
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An implementation may support additional subtypes of <tt>character</tt>
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that may or may not be supertypes of <tt>base-character</tt>.
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In addition, an implementation may define <tt>base-character</tt>
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to be equivalent to <tt>character</tt>. The choice of any base characters
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that are not standard characters is implementation-defined.
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Only base characters can be elements of a base string.
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No upper bound is specified for the number of distinct characters
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of type <tt>base-character</tt>-that is implementation-dependent-but the lower
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bound is 96, the number of standard Common Lisp characters.
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<br><img align=bottom alt="change_end" src="gif/change_end.gif">
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<P>
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<HR>
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<P><ADDRESS>
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AI.Repository@cs.cmu.edu
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